Structural and magnetic properties of the mechanically alloyed Fe50Co50 and (Fe50Co50)62Nb8B30 powder mixtures were studied by X-ray diffraction and vibrating sample magnetometry. For the Fe50Co50 powders, a bcc a-Fe(Co) solid solution with a lattice parameter close to 0.2861 nm is achieved after 24 h of milling. The magnetization increases gradually with milling time and saturates after 24 h (Ms = 215 emu/g). The soft magnetic properties (low values of coercivity, Hc, and squarness ratio Mr/Ms) point out that small magnetic particles are typically single domain. Nevertheless, for the (Fe50Co50)62Nb8B30 powders, a nanocomposite structure is achieved after 125 h of milling. The saturation magnetization decreases rapidly during the first hours of milling to about 15.24 emu/g and remains nearly constant on further milling. The coercivity, Hc, value is about 160 Oe.